Step 10: How to use the plasma speaker

Step 11: Interesting discharges...

Just a little story I like to tell you about... While I was testing (well, playing) my plasma speaker, the 12v battery is going flat and the arcs are...

Are you tired of those old black speakers that only just make sounds? Maybe sound reactive lights are just not enough to impress you? How about a Plasma Speaker?

A plasma speaker is a device that generates an high voltage electrical arc that makes purple light and music! Without any speakers or any moving parts! Sounds too good to be true? Well, you're wrong, the high voltage arc really does 'sing' by vibrating in the air. (Of course, you will need to give the device musical audio for it to work.) And just leave this instructable if you still don't believe me...

And this is something I always wanted to build - I have been dreaming to build one for about 6 months, until Kiteman has greatly boosted my encouragement to build one. (Thanks Kiteman!)

Step 1: The dangers you must know...

A plasma speaker is no toy...

Health HazardUnlike the ordinary speakers, the plasma speaker are dangerous high voltage device, do NOT attempt to build this device unless you know what you are doing... And do NOT even attempt to build one if you have heart problems or weak heart or wearing a pacemaker, because one little shock from this thing can put you out... I am not responsible for any injuries or deaths caused by this device.

Why should you know all of this? it is because you can ONLY live once, and no more...If you don't think that you shouldn't build one, just watch movies of it working instead, much better than risking your life to build and operate one.If you think you are okay to build one without killing your self, then move on to the next step.

Hazard to ElectronicsSince the plasma speaker generates high voltages, there is a chance there will be high voltage spikes on the low voltage side of the device, which can get onto the audio line and damage (or destroy) the player. They are some safety features to prevent the spikes damaging the player, but they can fail... So I am not responsible if your player gets damaged, and use cheap players like CD players, if you're rich, you can use expensive players if you want. :-)

I like the design and may attempt something similar sometime, however I did notice one thing in the schematic that would perhaps explain why the mosfet was getting so hot. there is no gate to ground resistor, meaning that the gate goes from 12v to 12v and high impedence when it should be going from high to low. the tl494 has an essentially open emitter output to the mosfet, otherwise I like the idea of using dead time control as modulation, very cool.

There is probable a pull down resistor in the tl494 or the mosfet gate, thus the circuit works in the first place, however the mosfet is probably switching slowly or partially, due to the high driving impedance on a low impedance gate. If the gate to ground resistor doesn't work, try heat sinking the mosfet along with it. I reccommend a resistor value of around 100-1000 ohms, try 1000 first.

I used my plasmaspeaker for over a year now but I have a problem. I always used a laptop power supply (90 watt) for the flyback transformer and last week I bought a heavyduty power supply (50 volt/16 amps, 800VA) and now I killed my MOSFET (IRF640). My question is; wich MOSFET can I use for pulling a few hundred watts without killing it. The max the IRF640 took was 26 volts and about 3.80 amps (at 30 volt and 4 amps it blew up). I had a 2SK1082 MOSFET laying arround but that doesnt work very well. I got a very little arc from that one.

Please help me, I really need a MOSFET that can handle much more current/voltage and still give a nice big fat arc from the flyback.

Thnx for the reply, I got 2 irfb20n50k's now. 500V 20A and I guess they can handle 280 watt at 25 degrees celcius. Atleast that is what I read in the datasheet. :) This MOSFET works great at 35V and 3.4A but I don't want to blow it up, haha. Got a 50V 16A (800VA) toroidal transformer attached to it with a variac and a 100V 22000uF capacitor. This MOSFET don't get that hot with a CPU cooler attached to it and I got a pretty long and loud arc. But I guess the MOSFET can handle even more! :) Here is a movie of my power supply and plasma speaker (only on 25V) :p

good idea about using a cooler but one side of them gets really hot so your just moving the problem. im probably wrong. will the cool side being heated by the MOSFET cancel out the other side from overheating.

Hey Crimson-Deity, Here is just another video of my plasma speaker at 34 volt this time. The arc is now longer and louder! :) I will probably crank the voltage up some more in the near future, but I really hope I don't pop the MOSFET. :P

Thnx, I still need to build the variac, bridge rectifier and capacitor in a box :) And maybe I will build a volt and amp meter in it aswell. Looks alot better then a separate volt and amp meter if u ask me! :) I bought this stuff a week ago so that's why it lays all over the floor. :p

About dying of MOSFETS, I guess if u stay in the voltage, amps and watt range of what they can handle, u will be fine and keep them cool as possible. :)

Alright. So i built this with blind luck (Many of the projects i try to replicate fail in some way shape or form...) And well, i was surprised it actually worked! The shock was electrifying!! (No pun intended) But alas, i do have an issue. When i powered it on, it worked at an extremely high frequency, but even worse, it blew out my power supply! Now, this was an older power supply i scavanged from a satellite dish box or something (It had +5 +12 +22 and +30 which was much better than my ATX, considering it only goes up to +12 volts...) This being the first time trying it out, i thought maybe it was a bad power supply that was already bad, i just finished it off. I was wrong. I pulled out my 12 volt SLA battery, to use that instead. Not sure if it was the power supply's fault last time, i decided to only turn it on for a few seconds. The cable leading to the board got really hot, the battery got warm (Uh oh...) and the mosftet got hot to the touch; Only in a matter of seconds! Thankfully, the battery is still ok at the time of writing, but what would be the cause of such an issue? I am thinking it may be shorting somewhere, but looking with my multimeter i dont seem to find any errors. Only the mosfet and the power cables get extremely warm as far as i know. Any ideas? Great 'able BTW, was very easy to follow and understand.

UPDATE: Alright, so i swapped out all the wires with 14 gauge wire, which by the way is complete overkill, and tried using an ATX power supply. The ATX didn't even try powering it, being way too high of a current for it to do anything... Any idea why this is happening?!

Is it possible to somehow use plasma globe (ball) as plasma speaker (ofc, when you take out the globe)? I have problem with flyback trasformer, I can't get it working somehow.. But, I have broken plasma ball so I have driver for ball which I don't need.. Thanx in advice.

For those of you interested in building a plasma speaker, there's a nice plasma speaker kit offered by excelphysics that includes everything you need to build one! http://excelphysics.com/collections/frontpage/products/arc-plasma-speaker-kit

Why do you have a separate power supply for the flyback? Isnt the power comming from the circuit? What i can see from the schematic it would be going to the Mosfet? Also, is it possible to use a Ignition coil instead of a Flyback?

Wait so do you need to use a battery? Will a power supply like this work for both the flyback and circuit simultaneously? If it's not steady enough I have a 12v VRM and some caps. About how much current does this use?

Hi, i didn't get how to wire the ground, have i to connect the two negatives of both battery and power supply together or is it somehow different? please help me, 'cause i've built all the rest right and it doesn't work. PS is there any difference in using a "non solid core copper wire" for the windings?

THe way this works is exactly like how we get fm radio or any radio. The actual audio signal is too weak for you to pick up fromany distance in comparison the audio here is too weak to power the plasma generation. So we need a carrier and that is the high frequency. High enough to power the plasma generation and as stated above when you set it too a vibration above what the human ear can pick up it is in essence silent (your dog will disagree) same with radio a carrier signal with enough power to transmit over a great distance is used and the actuall audio signal you pick up with your radio is mixed into this carrier and your reciever picks it out..

AMAZING STUFF I freakin love that you did this. I made a little prototype much like your original one. I was going to make a final one and was excited then I put the project down and it has been forgotten. That was almost ten years ago. I am once again excited about thi and am starting my build again. Thanks,

Nice job Ohh and to anyone else reading the warning given for this build is no joke and it isnt just a warning like be careful itll shock you It is very seriously do not do unless you are 100 percent sure you kow about the fundamentals of electricity. You must understand how electricity works and how to protect your self from its power. This can kill. If you have even a little doubt then you are not ready to do this. Go and read up on electricity there are uhndreds of tutorials on it. \ With that said anyone with the experience and knowledge will love the display this gives. I was amazed the first time it was to unbelievable